The invention relates to a base frame of a motor vehicle seat comprising two rail pairs, two front rockers, two rear rockers and one seat support which has two side parts, a front cross member and a rear cross member, wherein each rail pair is hinged to a side part via a front rocker and a rear rocker and an adjustment device is provided for the height adjustment of the seat support. Such a base frame is known from U.S. Pat. No. 6,502,798 B1.
In the case of base frames for motor vehicle seats, efforts are being made to keep the constructional height low. Furthermore, the room within the base frame is often taken up by different components and drives. This especially applies in the case where the vehicle seat is fully equipped with the maximum of the options offered by the manufacturer for adjusting and using the seat.
A combination of a sector wheel and pinion has gained general acceptance for a height adjustment mechanism of a base frame; in this context, reference is made, only by way of example, to the above-mentioned U.S. Pat. No. 6,502,798 B1; a combination of a toothed rack and locking mechanism is also being used, see, only by way of example, EP 1 190 891 B1. With regard to the prior art, reference is also made to U.S. Pat. No. 3,765,720 A and U.S. Pat. No. 5,622,406 A.
The aim is that, if possible, it is not both seat sides that are provided with components of the adjustment device and actively adjusted, but rather that only a single adjustment device is provided, if possible, which is more or less allocated to one seat side. In this case, the base frame is designed such that the other seat side is passively co-adjusted.
Based thereon, the invention has set itself the object of specifying a height-adjustable base frame for a motor vehicle seat which has a single adjustment device and as few components as possible, with common drive components being used, and which is suitable for a one-sided lock.